1. Technical Field
This invention relates generally to perches and guards for birds of prey on electrical power lines. More specifically, it relates to a convenient, but secure, clamp for attaching such perches and guards to electrical power line poles.
2. Background Art
Presently, birds of prey, or raptors, are vulnerable to shock and electrocution from electrical power lines. When the big birds land on electrical power line poles, they prefer the space on the pole crossbar between two parallel power lines. When they take off, however, they jump off the crossbar between the two lines, and, with the first downstroke of their wings, often touch both lines, causing a short circuit and electrocuting themselves. This phenomenon has resulted in the death of many such birds, and the interruption of electrical service to many utility customers.
Pacer Industries of Twin Falls, Idaho, produces a raptor guard for installation on power line pole crossbars. Pacer's guard is depicted in FIG. 1. The clamp system for this guard has two stationary L-shaped members which are on the same side, opposite a pair of inverted F-shaped members. Each inverted F-shaped member has a stationary portion, which is connected to one of the stationary L-shaped members, and a movable portion, which extends under the bottom side of the power pole crossbar. A straight coiled spring extends through the spine of the inverted F-shaped member to connect the stationary portion and the movable portion.
The Pacer clamp works reasonably well for attaching raptor guards. A guard is a device devoid of horizontal outside edges, which is attached to the pole crossbars. The outside edges may be vertical or steeply angled downwardly or upwardly, as depicted in FIG. 1. These nonhorizontal edges discourage the big birds from landing on the space protected by the guard.
There is a need, however, to provide safe perches for the raptors, as well as guards. The strategy is to encourage the birds to land where they will be safe, and to discourage them from landing where they may be hurt. A raptor protection unit of my design and including a perch is depicted in FIG. 2. For perches, the crossbar clamp must withstand great forces exerted by the big birds during landings and takeoffs. The Pacer clamp described above, designed for guards which needn't withstand the weight of the birds, will not hold up well for perch service. In particular, a twisting, rocking or lifting action exerted on the Pacer clamp by the big birds will often knock it loose from the crossbar, creating a risk for the bird and the electrical service.
There is a need then, for a raptor perch clamp which may be conveniently, but securely, attached to a power line pole crossbar. Also, there is a need for a raptor perch clamp which can repeatedly withstand the great forces of the big birds landing on it and taking off from it.